Effects of prolactin and growth hormone on protein synthesis in larval and adult frogs (Rana pipiens)

Muscle function, exercise capacity, physical activity level and cardiovascular disease risk factor knowledge in patients with prolactinoma

OBJECTIVE

Prolactinoma can increase the risk of cardiovascular diseases (CVDs), such as arterial stiffness, atherosclerosis, dysrhythmia and heart failure. This study aimed to evaluate and compare muscle function, exercise capacity, physical activity (PA) level, CVD risk factor knowledge level, sleep quality, fatigue and quality of life between prolactinoma patients and healthy controls.

METHODS

Nineteen female patients with prolactinomas and 19 healthy women were included in this study. Quadriceps muscle strength (QMS) was measured using a hand dynamometer, and muscular endurance was evaluated via the squat test. The 6-minute walking test (6MWT) distance was also measured. CVD risk factor knowledge levels were evaluated with the Cardiovascular Diseases Risk Factors Knowledge Level Scale (CARRF-KL), PA levels were assessed with the International Physical Activity Questionnaire-short form (IPAQ), sleep quality was assessed with the Pittsburgh Sleep Quality Index (PSQI), fatigue was assessed with the Multidimensional Fatigue Rating Scale (MAF), and quality of life was assessed with the Short Form-36 questionnaire (SF-36).

RESULTS

Patients with prolactinomas had significantly lower 6MWT distances; CARRF-KL total scores; SF-36 general health and physical limitation scores; and higher IPAQ-sitting scores than did healthy controls (p < 0.05). Moreover, there were no significant differences between the groups in terms of QMS score; number of squats; severity of IPAQ score; severity, moderate, or total walking score; total PSQI score; or total MAF score (p > 0.05).

CONCLUSIONS

Exercise capacity and quality of life are adversely affected, and sedentary behavior is observed in prolactinomas. Patients with prolactinomas have less knowledge about CVD risk factors than healthy individuals. CVD incidence and knowledge and functional capacity should be improved in patients with prolactinomas by the use of a multidisciplinary team for cardiac rehabilitation.

CLINICAL TRIAL REGISTRATION

This study is part of a larger clinical trial registered on ClinicalTrials.gov prior to participant enrollment (NCT05236829).

Nonalcoholic Fatty Liver Disease, Bone and Muscle Quality in Prolactinoma: A Pilot Study

OBJECTIVE

Hyperprolactinemia has negative impacts on metabolism and musculoskeletal health. In this study, individuals with active prolactinoma were evaluated for nonalcoholic fatty liver disease (NAFLD) and musculoskeletal health, which are underemphasized in the literature.

METHODS

Twelve active prolactinoma patients and twelve healthy controls matched by age, gender, and BMI were included. Magnetic resonance imaging-proton density fat fraction (MRI-PDFF) was used to evaluate hepatic steatosis and magnetic resonance elastography (MRE) to evaluate liver stiffness measurement (LSM). Abdominal muscle mass, and vertebral MRI-PDFF was also evaluated with MRI. Body compositions were evaluated by dual energy X-ray absorptiometry (DXA). The skeletal muscle quality (SMQ) was classified as normal, low and weak by using "handgrip strength/appendicular skeletal muscle mass (HGS/ASM)" ratio based on the cut-off values previously stated in the literature.

RESULTS

Prolactin, HbA1c and CRP levels were higher in prolactinoma patients (p<0.001, p=0.033 and p=0.035, respectively). The median MRI-PDFF and MRE-LSM were 3.0% (2.01-15.20) and 2.22 kPa (2.0-2.5) in the prolactinoma group and 2.5% (1.65-10.00) and 2.19 kPa (1.92-2.54) in the control group, respectively and similiar between groups. In prolactinoma patients, liver MRI-PDFF showed a positive and strong correlation with the duration of disease and traditional risk factors for NAFLD. Total, vertebral and pelvic bone mineral density was similar between groups, while vertebral MRI-PDFF tended to be higher in prolactinoma patients (p=0.075). Muscle mass and strength parameters were similar between groups, but HGS/ASM tended to be higher in prolactinoma patients (p=0.057). Muscle mass was low in 33.3% of prolactinoma patients and 66.6 of controls. According to SMQ, all prolactinoma patients had normal SMQ, whereas 66.6% of the controls had normal SMQ.

CONCLUSION

Prolactinoma patients demonstrated similar liver MRI-PDFF and MRE-LSM to controls despite their impaired metabolic profile and lower gonadal hormone levels. Hyperprolactinemia may improve muscle quality in prolactinoma patients despite hypogonadism.

Prolactin and tadpole metamorphosis. Evidence of prolactin receptors in premetamorphic Rana catesbeiana liver and tail fin

The binding characteristics of ovine prolactin (OPRL) to a particulate fraction from liver and tail fin of Rana catesbeiana tadpoles were studied. The specific binding of [125I]oPRL to both tissues was found to be a saturable process with a single class of binding sites in each tissue. Although the dissociation constants were similar for each tissue, the tail fin demonstrated a 10-fold higher binding capacity than the liver tissue. Pretreatment of the liver and tail fin particulate fractions with degradative enzymes revealed that trypsin and phospholipase C reduced the subsequent specific [125I]oPRL binding in both tissues. However, neuraminidase treatment decreased the prolactin binding in the liver while having no effect on the tail fin. The binding of prolactin to the amphibian tissues was found to be specific for prolactin and growth hormones. [125I]oPRL binding to both tissues was a reversible process although the dissociation rate was faster for the tail fin than for the liver. Therefore, prolactin receptors are associated with both a prolactin responsive tissue, the tail, and an unresponsive tissue, the liver, in the tadpole.