Any Decrease in Lung Function is Associated With Worse Clinical Outcomes: Post Hoc Analysis of the IMPACT Interventional Trial

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Impact of exacerbation history on long-term efficacy of dupilumab in patients with asthma

Background

The phase 3 QUEST (NCT02414854) and TRAVERSE (NCT02134028) studies demonstrated the efficacy of dupilumab 200/300 mg versus placebo every 2 weeks for 52 weeks (QUEST) and dupilumab 300 mg up to an additional 96 weeks (TRAVERSE) in patients ≥12 years of age with uncontrolled, moderate-to-severe asthma. Overall, safety was consistent with the known dupilumab safety profile. This post hoc analysis assessed long-term dupilumab efficacy for up to 3 years by exacerbation history.

Patients and methods

Unadjusted annualised severe exacerbation rates (AER) and change from parent study baseline (PSBL) in pre-bronchodilator forced expiratory volume in 1 s (FEV1) and 5-item Asthma Control Questionnaire (ACQ-5) score were assessed in patients with PSBL eosinophils ≥150 cells·µL-1 or fractional exhaled nitric oxide ≥20 ppb and 1 (n=624), 2 (n=344), or ≥3 (n=311) exacerbations in the year before enrolment in QUEST.

Results

In all three groups, dupilumab treatment progressively reduced AER range to 0.17-0.30 during TRAVERSE (Weeks 48-96), increased pre-bronchodilator FEV1 range by 0.28-0.49 L by Week 96 and improved asthma control (reduced ACQ-5 score range by 1.51-2.03 by Week 48). For patients who first received dupilumab upon TRAVERSE enrolment, AER decreased, and lung function and asthma control improved rapidly, as was observed upon initiation of dupilumab in QUEST. Dupilumab was efficacious regardless of exacerbation history.

Conclusion

For patients with uncontrolled, moderate-to-severe asthma with elevation of at least one type 2 biomarker, dupilumab treatment provides sustained, long-term reduction of exacerbation rates and improvements in lung function and asthma control irrespective of exacerbation history.

Identification of key opportunities for optimising the management of high-risk COPD patients in the UK using the CONQUEST quality standards: an observational longitudinal study

Background

This study compared management of high-risk COPD patients in the UK to national and international management recommendations and quality standards, including the COllaboratioN on QUality improvement initiative for achieving Excellence in STandards of COPD care (CONQUEST). The primary comparison was in 2019, but trends from 2000 to 2019 were also examined.

Methods

Patients identified in the Optimum Patient Care Research Database were categorised as newly diagnosed (≤12 months after diagnosis), already diagnosed, and potential COPD (smokers having exacerbation-like events). High-risk patients had a history of ≥2 moderate or ≥1 severe exacerbations in the previous 12 months.

Findings

For diagnosed patients, the median time between diagnosis and first meeting the high-risk criteria was 617 days (Q1-Q3: 3246). The use of spirometry for diagnosis increased dramatically after 2004 before plateauing and falling in recent years. In 2019, 41% (95% CI 39-44%; n = 550/1343) of newly diagnosed patients had no record of spirometry in the previous year, and 45% (95% CI 43-48%; n = 352/783) had no record of a COPD medication review within 6 months of treatment initiation or change. In 2019, 39% (n = 6893/17,858) of already diagnosed patients had no consideration of exacerbation rates, 46% (95% CI 45-47%; n = 4942/10,725) were not offered or referred for pulmonary rehabilitation, and 41% (95% CI 40-42%; n = 3026/7361) had not had a COPD review within 6 weeks of respiratory hospitalization.

Interpretation

Opportunities for early diagnosis of COPD patients at high risk of exacerbations are being missed. Newly and already diagnosed patients at high-risk are not being assessed or treated promptly. There is substantial scope to improve the assessment and treatment optimisation of these patients.

Funding

This study is conducted by the Observational & Pragmatic Research International Ltd and was co-funded by Optimum Patient Care and AstraZeneca. No funding was received by the Observational & Pragmatic Research Institute Pte Ltd (OPRI) for its contribution.

InforMing the PAthway of COPD Treatment (IMPACT Trial) Single-Inhaler Triple Therapy (Fluticasone Furoate/Umeclidinium/Vilanterol) Versus Fluticasone Furoate/Vilanterol and Umeclidinium/Vilanterol in Patients With COPD: Analysis of the Western Europe and North America Regions

BACKGROUND

The InforMing the Pathway of COPD Treatment (IMPACT) trial demonstrated lower moderate/severe exacerbation rates with fluticasone furoate/umeclidinium/vilanterol (FF/UMEC/VI) versus FF/VI or UMEC/VI in patients with chronic obstructive pulmonary disease (COPD) and a history of exacerbations. Since IMPACT was a global study, post-hoc analyses were conducted by geographic region to investigate potential differences in overall findings.

METHODS

IMPACT was a 52-week, randomized, double-blind trial. Patients with symptomatic COPD and ≥1 moderate/severe exacerbation in the prior year were randomized 2:2:1 to once-daily FF/UMEC/VI 100/62.5/25µg, FF/VI 100/25µg, or UMEC/VI 62.5/25µg. Endpoints assessed in the overall, Western Europe and North America populations included on-treatment moderate/severe exacerbation (rates and time-to-first), trough forced expiratory volume in 1 second and St George's Respiratory Questionnaire (SGRQ) total score. Safety was assessed.

RESULTS

Overall, 10,355 patients were enrolled, 3164 from Western Europe, 2639 from North America. FF/UMEC/VI significantly reduced on-treatment moderate/severe exacerbation rates versus FF/VI and UMEC/VI in Western Europe (rate ratios 0.82 [95%CI 0.74-0.91], P<.001 and 0.76 [0.67-0.87], P<.001) and in North America (0.87 [0.77-0.97], P=.014 and 0.69 [0.60-0.80], P<.001). FF/UMEC/VI reduced time-to-first moderate/severe exacerbation and improved lung function versus FF/VI and UMEC/VI in both regions, and improved SGRQ total score in Western Europe, but not North America. Safety profiles were generally similar between treatment groups/regions; the inhaled corticosteroid class effect of increased pneumonia incidence was seen in North America but not Western Europe.

CONCLUSION

Consistent with intent-to-treat results, FF/UMEC/VI reduced moderate/severe exacerbation rate and risk and improved lung function in Western Europe and North America; however, between-regions differences were seen for SGRQ total score and pneumonia incidence.

CLINICAL TRIAL REGISTRATION

NCT02164513.

Prognostic value of clinically important deterioration in COPD: IMPACT trial analysis

INTRODUCTION

Clinically important deterioration (CID) is a multicomponent measure for assessing disease worsening in chronic obstructive pulmonary disease (COPD). This analysis investigated the prognostic value of a CID event on future clinical outcomes and the effect of single-inhaler triple versus dual therapy on reducing CID risk in patients in the IMPACT trial.

METHODS

IMPACT was a phase III, double-blind, 52-week, multicentre trial. Patients with symptomatic COPD and at least one moderate/severe exacerbation in the prior year were randomised 2:2:1 to fluticasone furoate/umeclidinium/vilanterol (FF/UMEC/VI) 100/62.5/25 µg, FF/VI 100/25 µg or UMEC/VI 62.5/25 µg. CID at the time-point of interest was defined as a moderate/severe exacerbation, ≥100 mL decrease in trough forced expiratory volume in 1 s or deterioration in health status (increase of ≥4.0 units in St George's Respiratory Questionnaire total score or increase of ≥2.0 units in COPD Assessment Test score) from baseline. A treatment-independent post hoc prognostic analysis compared clinical outcomes up to week 52 in patients with/without a CID by week 28. A prospective analysis evaluated time to first CID with each treatment.

RESULTS

Patients with a CID by week 28 had significantly increased exacerbation rates after week 28, smaller improvements in lung function and health status at week 52 (all p<0.001), and increased risk of all-cause mortality after week 28 versus patients who were CID-free. FF/UMEC/VI significantly reduced CID risk versus dual therapies (all p<0.001).

CONCLUSIONS

Prevention of short-term disease worsening was associated with better long-term clinical outcomes. FF/UMEC/VI reduced CID risk versus dual therapies; this effect may improve long-term prognosis in this population.

Blood eosinophil count predicts treatment failure and hospital readmission for COPD

We examined associations between blood eosinophil counts (BEC) and risk of treatment failure or hospital readmission following acute oral corticosteroid (OCS)-treated COPD exacerbations. We conducted studies from the Optimum Patient Care Research Database (OPCRD) (www.optimumpatientcare.org/opcrd) and Clinical Practice Research Datalink (CPRD) (www.cprd.com/home/), validated databases for medical research, with linked Hospital Episode Statistics (HES) data for ∼20 000 COPD patients aged ≥40 years. For patients with OCS-treated COPD exacerbations treated in primary care, with BECs recorded on first day of OCS treatment (Cohort 1), we assessed treatment failure (COPD-related hospitalisations and OCS prescriptions beyond index OCS course). For patients hospitalised for COPD exacerbations, with BEC measured over an exacerbation-free period during the year prior to admission (Cohort 2), we assessed readmission rate. Cox proportional hazards regression analysis was adjusted for confounders to estimate the association between BEC and treatment outcomes. Of patients treated with OCS for COPD exacerbations in primary care (Cohort 1), 44% experienced treatment failure following single OCS courses, and 10% (255/2482) were hospitalised for ≤6 weeks. Greater BEC was associated with reduced hospital-admission risk (hazard ratio [HR]=0.26; 95% CI: 0.12-0.56, per 100 cells·µL-1 increase). BEC increases of ≥200 cells·µL-1 from exacerbation-free periods to exacerbations were associated with least hospitalisation risk (HR=0.32; 95% CI: 0.15-0.71) versus no BEC change. For patients hospitalised for COPD exacerbations (Cohort 2), 4-week hospital readmission was 12% (1189/10 245). BEC increases during an exacerbation-free period within the past year were associated with reduced risk of short-term readmission (HR=0.78; 95% CI: 0.63-0.96). Greater BEC predicted better outcomes for patients with OCS-treated COPD exacerbations, whether community or hospital managed. Eosinopenia predicted worse outcomes.

Distribution, Temporal Stability and Appropriateness of Therapy of Patients With COPD in the UK in Relation to GOLD 2019

BACKGROUND

The 2019 Global Initiative for Chronic Obstructive Lung Disease (GOLD) report made recommendations for the assessment, initial and subsequent treatment chronic obstructive pulmonary disease (COPD) based on biomarkers, including blood eosinophil counts.

METHODS

We evaluated the distribution of UK COPD patients initiating maintenance therapy and established patients by GOLD group, the prevalence of comorbidities and appropriateness of therapy using electronic patient records from the Optimum Patient Care Research Database (OPCRD). Changes in effective GOLD group, therapy and exacerbation rates over the next 2 years were analysed.

FINDINGS

11,409 established COPD patients and 699 starting therapy were studied. 44·3%, 25·7%, 13·8% & 16·2% of established COPD patients and 45·2%, 28·5%, 15·7% & 10·6% initiating therapy were in GOLD groups A, B, C & D respectively.The overall proportion in each GOLD group was similar after 2 years but there was substantial movement of patients between groups. Diabetes and cardiovascular disease were the most common comorbidities in all groups in both cohorts.LAMA monotherapy was the commonest initial therapy in all GOLD groups. In both cohorts there was over-treatment with escalation, de-escalation or switching in nearly 50% during follow-up.In both cohorts, exacerbation rates were highest in group D and appeared higher in over-treated patients.

INTERPRETATION

Most patients are not at risk of exacerbations and co-morbidities are common. Many patients change effective GOLD group and therapy over time. Prescribing is not in accordance with guideline recommendations and many patients still appear over treated.

Defining disease modification in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a debilitating condition characterized by airflow limitation that is not fully reversible. It is a major cause of morbidity and mortality and represents substantial economic and social burden throughout the world. A range of interventions has been developed that decrease symptoms and address complications associated with COPD. However, to date few interventions have been unequivocally demonstrated to modify disease progression. Assessment of the potential for interventions to modify disease progression is complicated by the lack of a clear definition of disease modification and disagreement over appropriate markers by which modification should be evaluated. To clarify these issues, a working group of physicians and scientists from the USA, Canada and Europe was convened. The proposed working definition of disease modification resulting from the group discussions was "an improvement in, or stabilization of, structural or functional parameters as a result of reduction in the rate of progression of these parameters which occurs whilst an intervention is applied and may persist even if the intervention is withdrawn". According to this definition, pharmacologic interventions may be considered disease-modifying if they provide consistent and sustained improvements in structural and functional parameters. Smoking cessation and lung volume reduction surgery would both qualify as disease-modifying interventions.

Living with severe chronic obstructive pulmonary disease (COPD): perceptions of patients and their carers. An interpretative phenomenological analysis

BACKGROUND

A study designed to explore the experiences of patients with severe chronic obstructive pulmonary disease (COPD) and their carers, particularly with regard to ongoing and palliative care needs.

METHODS

The participants were nine men and one woman with severe COPD and the carers of eight of the men, in East Devon, UK. Semi-structured interviews were undertaken, transcribed and analysed using interpretative phenomenological analysis (IPA).

RESULTS

The emergent themes were of losses, adaptation, relationships with health professionals and effect on carer. Losses reflected the loss of personal liberty and dignity and of previous expectations of the future. Adaptation included strategies to cope with the effects of the disease. Relationships related to both positive and negative aspects of contact with health professionals. There was appreciation for continuity of care and reassurance. The effect on the carer was evident particularly as they had to take on multiple roles. They also experienced some of the same losses as the patient and appeared enmeshed with the illness.

CONCLUSIONS

This study confirmed the inexorable decline in activities of daily life and social isolation for patients with severe COPD. Adaptive strategies were common and some positive aspects were identified. Support from the primary health care team was appreciated. The strain on carers was very apparent. The concept of a more structured sharing of information and a surveillance role mediated by health care professionals known to the patient and carer would be a pragmatic approach to improving care.

Asthma after childhood pneumonia: six year follow up study

OBJECTIVE

To establish the long term cumulative prevalence of asthma in children admitted to hospital with pneumonia and to examine the hypothesis that some children admitted to hospital with pneumonia may be presenting with undiagnosed asthma.

DESIGN

Prospective study of a cohort of children previously admitted to hospital with pneumonia, followed up by postal questionnaires to their general practitioners and the children or their parents.

SETTING

General practices in southwest England.

PARTICIPANTS

78 children admitted to the Royal Devon and Exeter Hospital between 1989 and 1991 with a diagnosis of pneumonia confirmed on independent review of x ray films.

MAIN OUTCOME MEASURES

Any diagnosis of asthma, use of any treatment for asthma, and asthma symptom scores.

RESULTS

On the basis of a 100% response rate from general practitioners and 86% from patients or parents, the cumulative prevalence of asthma was 45%. A diagnosis of asthma was associated with a family history of asthma (odds ratio 11.23; 95% confidence interval 2.57 to 56.36; P=0.0002). Mean symptom scores were higher for all children with asthma (mean score 2.4; chi(2)=14.88; P=0. 0001) and for children with asthma not being treated (mean 1.4; chi(2)=6.2; P=0.01) than for those without asthma (mean 0.2).

CONCLUSIONS

A considerable proportion of children presenting to a district general hospital with pneumonia either already have unrecognised asthma or subsequently develop asthma. The high cumulative prevalence of asthma suggests that careful follow up of such children is worth while. Asthma is undertreated in these children; a structured symptom questionnaire may help to identify and reduce morbidity due to undertreatment.

Home treatment of patients with cystic fibrosis using the 'Intermate': the first year's experience

Home treatment of patients with cystic fibrosis has many attractions and is becoming increasingly popular. The investigators have studied the use, results and costs of the first year of operation of a home-care intravenous antibiotic service using the 'Intermate' infusion device in a prospective study using questionnaires, spirometric and weight measurements. Ninety-three patients received 166 courses of intravenous antibiotics in full or in part at home during 1991. The average length of treatment was 12.5 days and on average 70% of the treatment was given at home. The mean percentage predicted FEV1 and FVC improved after treatment and the mean improvement was not significantly different to that produced by hospital treatment. Breathlessness, sputum volume, appetite, ability to sleep, mood, energy and overall well-being, as assessed by questionnaire, showed significant improvements after home treatment. The median time spent mixing and administering drugs was 10-19 hours and visiting the hospital was 7-12 hours. The median number of days of lost income to patients or their carers was 0 days. The majority of the patients were extremely satisfied with the treatment and supervision that they received. Using the home care service, 1442 inpatient days were saved. The investigators conclude that home care using 'Intermates' improves a patient's lung function and quality of life.

Respiratory symptoms, immunological responses, and aeroallergen concentrations at a sawmill

After identification of a case of extrinsic allergic alveolitis due to exposure to wood dust at a sawmill, all employees at the sawmill where he worked were studied with an occupational, environmental, and symptom questionnaire, spirometry, skin prick tests, and serum specific IgG measurements. Ninety five of current and 14 of 17 ex-sawmill workers were studied. As a basis for comparison, a group of 58 workers from a nearby light engineering factory were also studied. Few women (6) were employed and they were excluded from the analysis. Workers at the sawmill were stratified into high and low exposure groups depending on their place of work. This division was supported both by their subjective assessment of the dustiness of their environment and the results of personal dust samples. There were no significant differences between the three groups in age, height, smoking habits, exposure to other causes of extrinsic allergic alveolitis, forced expiratory volume in one second, forced vital capacity, atopic state, or cutaneous reactivity to moulds. In the high exposure group the prevalence of work related cough and nasal and eye symptoms was higher than in the low exposure and comparison groups. The prevalence of work related wheeze was similar in both the high exposure and comparison groups, but was lower in the low exposure group. The prevalences of chronic bronchitis and symptomatic bronchial hyper-reactivity were similar in the high and low exposure groups but were lower in the comparison group. Serum concentrations of specific IgG against extracts of sawdust and Trichoderma koningii were significantly higher in the high exposure group than in the other two groups. The prevalence of symptoms suggestive of extrinsic allergic alveolitis was 4.4% in the high exposure group, greater than in the low exposure group (0%), and the comparison group (1.9%). In conclusion extrinsic allergic alveolitis probably occurs in British sawmills, and among the exposed population its prevalence may be as high as that reported in Sweden. The allergen responsible is likely to be from mould growing on the wood and may be from Trichoderma koningii.

Extrinsic allergic alveolitis and asthma in a sawmill worker: case report and review of the literature

A 34 year old sawmill maintenance engineer developed a dry cough that was associated with widespread wheezes and crackles in his lungs. His symptoms worsened, with work related lethargy, fever, and breathlessness, and the loss of a stone in weight. At that time, while still at work, he had a neutrophil leucocytosis and increased concentration of gamma globulins. When seen subsequently some two months after stopping work, his chest radiograph and lung function tests were normal, but the cells recovered at bronchoalveolar lavage showed an increase in lymphocytes and mast cells, a pattern consistent with extrinsic allergic alveolitis. Serum precipitins were identified to extracts of sawdust, wood chips, and bark from the sawmill, and to eight species of mould grown from these samples. Specific IgG binding inhibition studies suggested that a common epitope present on Trichoderma koningii might be responsible for the cross reactivity of the patient's serum with the wood and fungal extracts. A diagnosis of wood associated extrinsic allergic alveolitis was made and since changing his job the patient has remained well. Wood associated allergic alveolitis has not previously been described in British sawmill workers, but has been reported in Sweden, with a prevalence of 5%-10% in exposed workers. A review of published data suggests extrinsic allergic alveolitis in wood workers is primarily caused by inhalation of the spores of contaminating fungi, but inhaled wood dust may exert a synergistic effect.

Type 1 Arnold-Chiari malformation in a 77 year old woman

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Serum testosterone levels in women with Cushing's disease

Serum testosterone was measured pre- and post-operatively in 31 women who obtained remission of Cushing's disease following treatment by interstitial irradiation of the pituitary gland. The mean serum testosterone was initially elevated at 3.35 nmol/l, with values ranging from 0.7 to 14.4 nmol/l. Following treatment the mean serum testosterone fell to 1.42 nmol/l (i.e. normal) and all but one of the 15 patients with initially elevated pre-treatment values obtained normal levels. The pretreatment testosterone concentrations correlated significantly (r = 0.47; p = 0.019) with the midnight ACTH concentration. The likely determinant of the raised serum testosterone would appear to be the intensity of the ACTH drive, although an individual's inherent sensitivity to ACTH may also be a factor.

Effects of short-term injection of gonadotrophins on ovarian follicle development in hypogonadal (hpg) mice

Twice daily injections of purified ovine and human FSH were used to investigate the control of ovarian follicle development in hypogonadotrophic hypogonadal (hpg) mice. Treatment for 5 days with doses greater than 3 micrograms resulted in a significant increase in the total number of growing follicles and the development of antral follicles. This was associated with increases in uterine weights and vaginal opening, indicating that steroidogenesis had also been stimulated. Further studies of the effects of combined injections of FSH and LH, linked with morphological analysis of ovarian interstitial cells, suggested that any contribution of background or contaminating LH to the effects of the FSH injections was minimal. It therefore appears that, in mice, FSH alone is capable of stimulating an increase in the initiation of follicle growth, of triggering the development of antral follicles, and supporting ovarian steroidogenesis.

Effects of gonadotrophin deficiency on follicular development in hypogonadal (hpg) mice

The rates of follicle growth and death in GnRH-deficient hypogonadal (hpg) mice and in normal mice were studied using the stochastic compartmental model of follicle dynamics. The rate estimates derived from this model suggest that in normal mice gonadotrophins act at several stages in the development of ovarian follicles. Gonadotrophins appear to regulate the number of follicles beginning to grow by controlling both the rate at which non-growing follicles enter the growing pool and the loss of non-growing follicles to atresia. They also appear to promote the growth of medium-sized follicles by reducing the rate of loss to atresia of these follicles rather than by stimulating growth per se. Furthermore, these data suggest that an intra-ovarian autoregulatory mechanism may exist to control the number of large follicles that are formed.

Postnatal ovarian follicle development in hypogonadal (hpg) and normal mice and associated changes in the hypothalamic-pituitary ovarian axis

Significant uterine growth occurred in normal and hypogonadal (hpg) mice between Days 7 and 21 but thereafter no further growth was observed in hpg mice. The ovaries of hpg mice were significantly smaller than those of normals at all ages, but there was no significant difference between the number of non-growing follicles in the ovaries of mutants and their normal littermates at any age studied, and normal and hpg mice showed a marked reduction in the number of non-growing follicles during the first month of life. The size and composition of the growing follicle population in hpg mice, however, differed markedly from those in normal animals and by 21 days of age the number of growing follicles in mutants was significantly reduced. There was no significant difference in the number of Type 3b follicles before 60 days of age, but the number of all other follicle types was significantly less in hpg mice at all ages studied. Follicles in which the antrum is fully developed (Type 7 and 8) were never seen in the ovaries of mutants and corpora lutea were never observed. Interstitial tissue development was also very poor in hpg ovaries. The hypothalamic GnRH content in normal mice remained low until Day 20, before rising sharply to adult levels (approximately 800 pg) between Days 20 and 30. The pituitary FSH content increased over the first 10 days of life to reach a peak of about 5000 ng, before declining to the adult value of about 2000 ng by Day 30, whilst the plasma FSH concentration was high in the first 10 days, but fell to adult levels over the next 20 days. Pituitary LH content increased significantly between Days 5 and 10 to reach the adult level of about 600 ng. Hypothalamic GnRH was undetectable at all ages in hypogonadal mice, but the pituitary content of FSH and LH had risen to the attenuated mutant adult value by Day 15, and unlike normals, plasma FSH concentrations were not elevated during the neonatal period. These results suggest that minimal gonadotrophic stimulation of the ovary from birth has no effect on the total number of follicles but reduces the number of growing follicles and prevents follicle growth beyond the early antral stage. Gonadotrophins therefore appear to have a role in the initiation and continuance of follicle growth in the adult mouse.

Prolactin measurements in normal and hypogonadal (hpg) mice: developmental and experimental studies

Plasma and pituitary PRL levels are significantly greater in adult female than in male rats. This difference is thought to be brought about by ovarian steroids. We found a similar sex difference in pituitary PRL content in normal mice from 30 days of age. Ovariectomy reduced pituitary PRL content and this reduction was prevented by sc implants of estradiol-17 beta (E2). Implants of E2 also increased the pituitary PRL content in normal male mice to a level approaching that in normal females. The hypogonadal (hpg) mice did not show a sex difference in pituitary PRL content. Implantation of E2 into mutants of both sexes raised the pituitary content of PRL to the level in normal females. Treatment of intact but not ovariectomized hpg females with two injections/day of 6 micrograms FSH (NIH-FSH-S15) produced uterine growth and an increase in pituitary PRL content. Estrogen implants significantly increased plasma PRL concentrations in ovariectomized normal female and normal male mice but not in adult hpg male or female animals. These results show that elevation of the plasma E2 concentration increased significantly the synthesis of PRL in both normal and hpg mice of both sexes, and in the normal, but not the hpg mice, also increased the plasma concentration of PRL.

Distribution of 125I-labelled follicle-stimulating hormone and human chorionic gonadotrophin in the gonads of hypogonadal (hpg) mice

Hypogonadal mice are deficient in LH releasing hormone (LH-RH), the releasing factor for LH and FSH, with a consequent failure of postnatal ovarian and testicular development. After intravenous injection of hypogonadal females with 125I-labelled human chorionic gonadotrophin (hCG), followed by autoradiography of semi-thin (1 micrometer) slices of the ovary, labelled hCG was found to be associated with interstitial cells and thecal cells with little or no labelling of granulosa cells. Labelled human FSH was associated solely with granulosa cells. Hypogonadal females, implanted for 5 days with a silicone elastomer capsule of oestrogen, showed a similar response to that of normal females with hCG labelling of the granulosa cells of the larger follicles as well as of the thecal cell layer. Furthermore, subcutaneous injection of hypogonadal females with LH-RH (50 ng), 12 times daily for 5 days, increased uterine weight and stimulated ovarian development with some large follicles binding hCG to both thecal and granulosa cells. Therefore stimulation of follicular development may possibly be associated with increased oestradiol concentrations. In the male, after injection of 125-I-labelled hCG, silver grains were associated with the interstitial cells alone in both hypogonadal and normal mice. Labelled human FSH was undetectable in semi-thin testicular sections, but the mode of injection (intravenous) not have allowed enough labelled hormone to reach the testis in order to resolve the question as to whether the hypogonadal or normal testis can bind FSH.