Temporal patterns of growth hormone, prolactin and thyrotropin secretion in Targhee rams selected for rate and efficiency of gain

Thirteen Targhee rams selected for rate and efficiency of gain for 4 yr (1.5 generations) were compared with 10 rams from a Targhee line with no selection for over 20 yr to determine if selection for these traits would be associated with changes in the secretion of growth hormone (GH), thyrotropin (TSH) and(or) prolactin (PRL). Selected rams exhibited greater birth weight, average daily gain (ADG) and feed consumed/day during a 6-wk individual feeding regimen, and exhibited greater overall ADG during a 16-wk feeding trial as compared with the unselected rams. Temporal blood plasma samples were collected at 15-min intervals for 8 h from each of the 23 rams for hormone analysis. Selected rams exhibited greater overall mean GH (6.1 +/- .4 vs 4.6 +/- .5 ng/ml), overall mean TSH (8.6 +/- 1.2 vs 6.2 +/- .7 ng/ml) and baseline mean TSH (8.0 +/- 1.1 vs 5.6 +/- .5 ng/ml) than the unselected rams. Although the adjusted GH spike amplitude value was higher in the selected line (12.1 +/- 3.0 vs 7.4 +/- .8 ng/ml), this difference was not significant. No differences were observed with any of the variables of PRL secretion. In addition, there were no significant correlations between any of the hormone variables and any of the feed or gain data. These data support the hypothesis that Targhee rams selected for rate and efficiency of gain exhibit higher plasma levels of GH and TSH than unselected rams of the same breed.

Treatment of small cell lung cancer with VP-16, vincristine, doxorubicin (Adriamycin), cyclophosphamide (EVAC), and high-dose chest radiotherapy

Seventy-one previously untreated patients with small cell lung cancer (SCLC) received a combination of VP-16, vincristine, doxorubicin (Adriamycin), and cyclophosphamide (EVAC) repeated every three weeks. Limited-disease (LD) patients and extensive-disease (ED) patients achieving a complete response (CR) or partial response (PR) after four to six cycles of EVAC received 4,000 rads over four weeks whole-brain radiotherapy (RT) and 5,000 rads over five weeks RT to the original pulmonary primary and mediastinum. ED patients with persisting disease outside the chest after six cycles of EVAC continued chemotherapy and did not receive RT. After RT was completed, EVAC was continued for a total treatment duration of 24 months. Of 65 patients evaluable for response 76% (25 of 33) of LD patients and 34% (11 of 32) of ED patients achieved a CR prior to RT; two additional ED patients achieved a CR after RT. Median survival for all 71 patients was 48 weeks (range, one to 207 weeks); median survival for 33 LD patients was 92 weeks and for 38 ED patients it was 36 weeks. Nine of 25 LD patients and 10 of 13 ED patients have relapsed from CR. The EVAC-RT protocol is promising in view of the high CR rate and long remission duration achieved, especially among patients with LD.

Hypothalamic control of endocrine thermogenesis

Hypothalamic and ruminal cooling raised serum thyrotropin (TSH), adrenocorticotropin (ACTH), norepinephrine (NE), and glucose in conscious goats in 20 degree C ambient temperature. Cooling of the preoptic anterior hypothalamus (POAH) for 2 h initially evoked shivering and vasoconstriction, leading to 1.5 degree C rise in rectal temperature (Tr). Pituitary-thyroid activation by POAH cooling was shown by peak rises in TSH of 60% at 40 min, in triiodothyronine (T3) of 54% at 80 min, and in thyroxine (T4) of 40% at 140 min. At 60 min, ACTH and NE peaked at 57 and 65%, respectively. TSH, ACTH, and NE declined during the 2nd h of POAH cooling as Tr plateaued; when POAH cooling was stopped, these hormones fell below basal level as vasodilation and panting restored Tr to normal. In contrast to the core hyperthermia evoked by POAH cooling, ruminal intubation with O degree C water (1 liter/10 kg) led to general hypothermia, Tpoah and Tr falling 1.6 degree C at 40 min. Pituitary-thyroid responses were less but ACTH and NE more, compared with POAH cooling. TSH peaked at 37% at 20 min, T3 at 55% at 60 min, and T4 at 18% at 200 min. ACTH peaked at 250% at 30 min and NE at 120% at 20 min. Thermosensitive neurons in the POAH seem to mediate more sensitive and complete control over TSH than over ACTH, or NE release, whereas extrahypothalamic core thermosensitivity (e.g., brain stem, spinal cord, abdomen) may influence ACTH and NE more than TSH release.

Plasma growth hormone, prolactin and thyrotropin secretory patterns in Hereford and Simmental calves

An experiment was conducted to test the hypothesis that bull calves of a larger, faster growing breed of cattle exhibit greater secretory activity of anabolic pituitary hormones than bull calves of a smaller, slower growing breed. Calves of both breeds were raised under similar conditions and maintained on the same diet for approximately 4 weeks before the blood sampling period. Simmental bull calves had higher (P less than .01) average daily gains and a heavier (P less than .01) mean body weight than Hereford bull calves. Overall plasma growth hormone (GH) concentrations were higher (P less than .01) in Simmental bull calves than in Hereford bull calves. Mean baseline GH was also higher (P less than .05) in Simmentals. Overall and baseline concentrations of prolactin (PRL) were similar for both breeds. Mean amplitude of PRL secretory spikes was higher (P less than .05) for Simmental than for Hereford bull calves. There was no breed effect on any variable of thyrotropin secretion. These data suggest that representatives of a larger, faster growing breed of cattle (Simmental) exhibit greater secretory activity of GH and PRL than do representatives of a smaller, slower growing breed (Hereford).

Use of active immunization against prolactin to study the influence of prolactin on growth and reproduction in the ram

An experiment was conducted to determine whether prolactin (PRL) is involved in the maintenance of reproductive tissue weights and body growth in yearling rams. Suppression of circulating PRL was achieved by active antibody production against bovine PRL. Free plasma PRL concentrations in immunized rams were decreased (P less than .05) by 73% after 3 months of treatment and 91% after 10 months of treatment in relation to concentrations in control rams. Average daily gain and final body weight were lower (P less than .05) for rams with suppressed circulating PRL (.042 kg/day and 67.0 kg for treatment rams and .060 kg/day and 72.7 kg for control rams). Although testes weights were 32% lower for the treated rams, antibody treatment did not affect (P greater than .05) the weights of the testes or accessory sex glands. No treatment effect was noted on plasma luteinizing hormone (LH), growth hormone (GH) or thyrotropin (TSH). Seasonal differences were observed in some variables of LH, GH and TSH secretion. Mean baseline LH for all animals was higher (P less than .01) in December than in March, June or September. Overall and baseline concentration of GH and TSh were highest (P less than .01) in December. These data suggest that (1) PRL is involved in body growth of the yearling ram, and (2) PRL may have a role in the maintenance of reproductive tissue weights in the yearling ram.

Prediction of outcome in metastatic breast cancer treated with adriamycin combination chemotherapy

Univariate and multivariate regression methods were used to analyze 17 potential clinical prognostic factors among 138 patients with advanced breast cancer who received Adriamycin-cyclophosphamide combination chemotherapy between 1973 and 1977 at the University of Arizona. Follow-up of patients was through September 1979, and survival data were nearly complete. Different factors varied in the relationship to outcome, but age, treatment, and response were important. Selecting the three most strongly related factors, predictive regression equations were developed, which described three types of possible outcome: 1) objective response (age, treatment, and liver involvement), 2) freedom from relapse (age, lung involvement, and response), and 3) survival (age, the number of involved sites [less than or equal to 2 or > 2], and treatment). Since use of the regression equations is cumbersome for clinical practice, three simplified tables were constructed to readily predict response, duration of response, and survival before the initiation of treatment.

Comparison of luteinizing hormone and prolactin levels in cycling and anestrous ewes

Concentrations of luteinizing hormone (LH) and prolactin (Prl) in the serum of anestrous and cycling ewes were compared. The concentration of LH in serum and the frequency of episodic releases of LH were lower in anestrous than in cycling ewes. Concentrations of LH in serum rose as rapidly after ovariectomy of anestrous ewes as after ovariectomy of cycling ewes. Prl levels were higher during anestrus than at any stage of the estrous cycle; however, high Prl levels were not necessarily associated either with low LH levels or the absence of episodic release of LH. These data suggest: (1) that anestrus is not due to a reduction in the intrinsic ability of the hypothalamo-hypophyseal system to secrete LH, and (2) that high Prl levels may be a symptom rather than a cause of seasonal anestrus.

Thyrotropin and prolactin secretory patterns during 24-hours infusion of thyrotropin-releasing hormone in calves

Plasma levels of thyrotropin (TSH), prolactin (Prl), growth hormone (GH), thyroxine (T4), and triiodothyronine (T3) were measured in response to continuous 24-h infusion of synthetic thyrotropin-releasing hormone (TRH) in normal and surgically thyroidectomized (THYX) calves in a series of 2 experiments. In the 1st experiment, the low dose of TRH (0.077 microgram/min) had no effect on any hormone levels measured. Plasma TSH concentration increased significantly (p less than 0.05) in response to TRH infusion (0.77 microgram/min) in both experiments, but plasma TSH levels plateaued and then declined in both cases despite continued TRH infusion and irrespective of the presence or absence of a thyroid gland. A similar pattern of secretion, though less markedly decreased over time, was observed for plasma Prl in both experiments. The higher dose (0.77 microgram/min) of TRH had no effect on plasma GH concentration in the 1st infusion, but did result in a significant (p less than 0.05) increase in overall mean concentration of GH in both normal and THYX calves in the 2nd experiment. Removal of the thyroid gland, thus removing the source of increasing T4 and T3 levels seen in normal calves infused with TRH, failed to alter the secretory patterns of TSH and Prl. These data suggest that feedback inhibition by increasing plasma thyroid hormone concentrations was not responsible for the failure of TSH and, to a lesser extent, Prl to maintain chronically elevated plasma levels in response to continuous 24-h TRH infusion. It is suggested that a depletion of pituitary TSH and Prl stores readily secretable in response to a constant dosage level of TRH may be responsible for the secretory patterns observed.

Episodic growth hormone secretory patterns in sheep: relationship to gonadal steroid hormones

The influence of anabolic steroids on growth hormone (GH) secretion in ruminants remains unclear, perhaps because of the dynamic nature of GH secretion. In the present study, blood samples were obtained at 15-min intervals for 12 h from intact ram lambs, ram lambs castrated postpubertally, and castrated ram lambs treated with either testosterone propionate (TP) or diethylstilbestrol (DES). Intact rams exhibited GH secretory episodes of greater (P less than 0.01) amplitude than did castrated lambs. Similarly, mean base-line and mean overall GH concentrations were higher (P less than 0.01) in rams than in castrates. Treatment of castrates with either TP or DES resulted in increased base-line (P less than 0.05) and overall (P less than 0.05) GH concentrations compared to untreated castrates. Although amplitude of GH spikes was larger in TP and DES groups, this difference was not statistically significant (P greater than 0.05). Because numerous studies have demonstrated that intact rams and castrates treated with TP or DES grow faster than untreated castrates, the data in the present study support the hypothesis that the anabolic action of androgens and estrogens is due, at least in part, to their influence on GH secretion.

Pituitary secretes to brain. Experiments in sheep

Because vascular casts of the pituitary demonstrated that there are a few venous connections from the adenohypophysis to the juxtaposed cavernous sinus, it was predicted that some portal vessels must carry blood from the adenohypophysis back to the neurohypophysis. Physiological studies confirmed this prediction and verified earlier observations that blood-flow within the neurohypophysis can be towards the median eminence. In the present study, increased concentrations of prolactin and growth hormone were found in blood sampled from intracranial vessels (internal carotid artery and sagittal sinus). It was concluded that the neurohypophyseal capillary bed not only receives trophic hormones produced in the adenohypophysis but, under certain physiological circumstances, delivers those hormones directly to the brain.

Influence of prostaglandins and thyrotropin releasing hormone (TRH) on hormone secretion and growth in wether lambs

A series of experiments were conducted in ewes and whether (castrate male) lambs to evaluate the influence of prostaglandins on secretion of anabolic hormones and to determine if repeated injections of prostaglandin (PG) F2alpha would chronically influence the secretion of these hormones and perhaps growth rate as well. A single intravenous injection of PGA1 and PGB1 (100 microgram/kg) exerted no significant (P greater than .10) influence on plasma concentrations of prolactin (PRL), growth hormone (GH) or thyrotropin (TSH) in ewes. PGA1, but not PGB1, stimulated an increase in the plasma concentration of insulin. Infusion of PGF2alpha for 5.5 hr into ewes resulted in increased (P less than .05) plasma concentrations of both GH and ARL while TSH and insulin were not significantly influenced. Prostaglandin F2alpha, when injected subcutaneously into wether lambs (10 mg twice weekly) stimulated (P less than .05) plasma GH concentrations after the first injection, but not after 3 weeks of treatment. Changes in plasma PRL or TSH were not observed consistently in the lambs treated chronically with PGF2alpha or TRH. Prostaglandin F2alpha, in the present studies, and PGE1 in previously reported studies (1-3), has been demonstrated to be stimulatory to the secretion of PRL and GH. In contrast, PGA1 and PGB1, which lack an 11-hydroxyl group, failed to influence the secretion of either PRL or GH. It would, therefore, appear that the 11-hydroxyl group is a structural requirement for prostaglandins to influence the secretion of these two hormones in sheep. Treatment with thyrotropin releasing hormone (TRH), alone or in combination with PGF 2alpha, significantly (P less than .05) increased growth rate (average daily gains) while PGF2alpha did not, despite the fact that both compounds exerted similar effects on plasma GH.