Stimulatory Effect of Luteinizing Hormone and Human Chorionic Gonadotropin on Testicular Prolactin Receptor Levels

• Published in: Biology of reproduction Vol. 23; no. 5; pp. 924 - 928
• Main Authors: Kelly, P A, Séguin, C, Cusan, L, Labrie, F
• Format: Journal Article
• Language: English
• Published: United States Society for the Study of Reproduction 01-12-1980
• Subjects: Animals; Chorionic Gonadotropin - pharmacology; Hypophysectomy; Kinetics; Luteinizing Hormone - pharmacology; Male; Prolactin - metabolism; Rats; Receptors, Cell Surface - metabolism; Receptors, Prolactin; Testis - drug effects; Testis - metabolism
• ISSN: 0006-3363; 1529-7268
• DOI: 10.1095/biolreprod23.5.924

A possible effect of LH or hCG on testicular prolactin receptor levels was investigated in
hypophysectomized adult rats. Hypophysectomy leads to a progressive decrease of testicular
prolactin receptor content to ∼25% of that of controls 12 days after surgery. In animals injected 3
times a day for 10 days with highly purified preparations of ovine LH or hCG, prolactin receptor
levels increased from 21 ± 4 to 41 ± 4 and 71 ± 7 fmol/testis, respectively (P<0.01 for both). The
increase in the number of testicular prolactin receptor levels observed after treatment with hCG in
hypophysectomized rats could not be duplicated by injection of estradiol-17β (0.5 µg), testosterone (200 µg) or 5α-dihydrotestosterone
(200 µg) given twice a day for 5 days. Moreover, these
steroids do not interfere with the stimulation of prolactin binding induced by hCG. Since treatment with prolactin is well
known to stimulate testicular LH binding and steroidogenesis, the
present data provide further evidence for a close interaction between prolactin and LH in the
control of the testicular levels of receptors for these two hormones and their subsequent role in the
control of testicular functions.