Endocrine Responses of the Prepubertal Male Rat to Hemiorchidectomy

• Published in: Biology of reproduction Vol. 17; no. 5; pp. 661 - 667
• Main Author: Moger, W H
• Format: Journal Article
• Language: English
• Published: United States Society for the Study of Reproduction 01-12-1977
• Subjects: Age Factors; Animals; Castration; Estradiol - metabolism; Follicle Stimulating Hormone - blood; Luteinizing Hormone - blood; Luteinizing Hormone - pharmacology; Male; Rats; Sexual Maturation; Testis - anatomy & histology; Testis - metabolism; Testosterone - metabolism
• ISSN: 0006-3363; 1529-7268
• DOI: 10.1095/biolreprod17.5.661

The effect of hemiorchidectomy on pubertal development was studied in animals operated on
at 25 days of age. Hemiorchidectomy significantly increased serum FSH concentrations at all ages
studied (30 to 55 days of age). Significant compensatory hypertrophy of the remaining testis occurred by 45 days of age in
one experiment and by 39 days of age in another. Serum LH concentrations were significantly increased and testosterone concentration
significantly decreased by
hemiorchidectomy. The increase in LH was less pronounced than that of FSH and was not observed in all experiments. Testicular
testosterone and estradiol concentrations were unaffected by
the operation. The pubertal increase in serum and testicular testosterone concentrations and the
acceleration of ventral prostate growth occurred at the same ages in hemiorchidectomized and
sham operated animals. Acute stimulation with exogenous LH resulted in equivalent serum testosterone concentrations in animals
hemiorchidectomized acutely or animals of the same age hemiorchidectomized 5 or 14 days previously. These experiments indicate
that hemiorchidectomy
causes a disturbance of the hypothalamic-pituitary-testicular axis resulting primarily in elevated scrum FSH concentrations
but that this disturbance has little effect on the endocrine changes associated with puberty in the male rat.