HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Schanbacher, B. D. Search for Related Content PubMed PubMed Citation Articles by Schanbacher, B. D.

Relationship of In Vitro Gonadotropin Binding to Bovine Testes and the Onset of Spermatogenesis¹

U. S. Department of Agriculture^2,3,, Clay Center, NE 68933

Abstract

Concentrations of luteinizing hormone (LH) and follicle stimulating hormone (FSH) were determined in serum of crossbred beef bulls during pubertal development. Serum LH ranged between .5 and 2.0 ng/ml with highest concentrations observed as 12 months of age. Serum FSH varied considerably among individuals but mean concentrations were within the normal range (50 to 100 ng/ml). Neither LH nor FSH increased at the time when testosterone increased or spermatogenesis entered meiosis.

Specific binding of ^{1 2 5}I-labeled human chorionic gonadotropin (hCG) and ^{1 2 5} I-labeled FSH to the bovine testis was demonstrated by autoradiographic localization techniques. Binding of ^{1 2 5}I-hCG and ^{1 2 5} I-FSH was preferentially located over interstitial tissue and seminiferous epithelial cells, respectively. An abundance of binding sites in newborn and 4-month-old calf testes shows that receptors for LH and FSH are present in the immature bovine testis.

Initiation of spermatogenesis was assessed by estimating the number of testicular sperm by histological and cytometric techniques following castration of bull calves at monthly intervals from birth to 12 months. Although spermatogenesis was qualitatively complete at 7 months, spermatogenesis and total daily sperm production were highest in 12-month-old animals. A high correlation (r = .98, P<.01) was found between sperm per gram testis and total daily sperm production. A parallel increase in serum testosterone of young bulls and testes weight (r = .95, P<.01) and total daily sperm production (r = .87, P<.05) suggest that initiation of spermatogenesis could be dependent on increased testosterone.

¹ The author acknowledges the National Institutes of Health, NIAMDD, Bethesda, MD, for purified LH, purified hCG, bovine LH (NIH-LH-B10) and bovine FSH (NIH-FSH-B1); Dr. D. J. Bolt, USDA, Beltsville, MD, for LH antisera (DJB 3-12/11); Dr. K. W. Cheng, University of Manitoba, Winnipeg, for purified FSH and FSH antisera used in this study. The technical assistance of Ms. Becky Chmelka and cooperation of the Nebraska Agricultural Experiment Station, University of Nebraska, Lincoln, are acknowledged.

² U. S. Meat Animal Research Center, Federal Research, Science and Education Administration.

³ Mention of a trade name, proprietary product or specific equipment does not constitute a guarantee or warranty by the U. S. Department of Agriculture and does not imply its approval to the exclusion of other products that may also be suitable

This article has been cited by other articles:

				E T Bagu, S Cook, C L Gratton, and N C Rawlings Postnatal changes in testicular gonadotropin receptors, serum gonadotropin, and testosterone concentrations and functional development of the testes in bulls. Reproduction, September 1, 2006; 132(3): 403 - 411. [Abstract] [Full Text] [PDF]