Premium
Calcitonin inhibits testosterone and luteinizing hormone secretion through a mechanism involving an increase in camp production in rats
Author(s) -
Wang Paulus S.,
Tsai ShiowChwen,
Hwang GueyShyang,
Wang ShyiWu,
Lu ChienChen,
Chen JiannJong,
Liu ShyRong,
Lee KunYih,
Chien Eileen Jea,
Chien ChauHeng,
Lee HsienYang,
Lau ChinPang,
Tsai ChingLin
Publication year - 1994
Publication title -
journal of bone and mineral research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.882
H-Index - 241
eISSN - 1523-4681
pISSN - 0884-0431
DOI - 10.1002/jbmr.5650091011
Subject(s) - calcitonin , medicine , endocrinology , luteinizing hormone , radioimmunoassay , human chorionic gonadotropin , anterior pituitary , testosterone (patch) , chemistry , calcitonin gene related peptide , hormone , calcium , neuropeptide , receptor
Effects of calcitonin peptides, including human calcitonin (hCT), salmon calcitonin (sCT), and calcitonin gene‐related peptide (CGRP), on the secretion of testosterone and luteinizing hormone (LH) in male rats were studied. Male rats were injected intravenously with human chorionic gonadotropin (hCG), calcitonin peptides, or hCG plus calcitonin peptides. Blood samples were collected at several intervals following hormone challenge. In an in vitro experiment, testis blocks were incubated with hCG (0, 0.05, 0.5, or 5 IU/ml) or hCG (0.5 IU/ml) plus calcitonin peptides (0–10 −9 or 10 −6 M) at 34°C for 30 minutes. Both medium and plasma samples were extracted by ether and analyzed for testosterone by radioimmunoassay (RIA). The concentration of calcium in each plasma sample was measured by an automatic calcium analyzer. The anterior pituitary gland (AP) was incubated with or without calcitonin peptides (0–10 nM) at 37°C for 30 minutes. They were then incubated with gonadotropin releasing hormone (GnRH, 10 nM) for a further 30 minutes. The concentration of LH in AP medium was measured by RIA. The accumulation of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) in both testicular tissues and APs were measured by RIA. A single intravenous injection of calcitonin peptides decreased the basal and hCG‐stimulated levels of plasma testosterone gradually from 60 to 180 or 360 minutes after challenge. The plasma calcium was not altered by the injection of calcitonin peptides and/or hCG. Administration of calcitonin peptides in vitro resulted in a dose‐dependent inhibition of both basal and hCG‐stimulated release of testosterone. Meanwhile, calcitonin peptides caused a dose‐dependent inhibition of the basal release of LH in vitro from rat APs. The content of cAMP in both testes and APs was increased by all calcitonin peptides. Neither hCT nor sCT altered the content of cGMP in testes and APs. These results suggest that calcitonin peptides, including hCT, sCT, and CGRP, inhibit the spontaneous and gonadotropin‐stimulated secretion of testosterone by acting directly at testes and reducing the release of pituitary LH through a mechanism involving an increase in cAMP production.