Damon C. Herbert, Ph.D.Professor
University of California, San Francisco, 1973
Dr. Herbert is Co-course Director of Dental Histology; lecturer in the Animal Models Course for graduate students; lecturer and laboratory instructor in Medical Histology. He also serves as the graduate, student advisor.
My general area of research has been in the area of pituitary histophysiology and reproductive biology. We have investigated the interrelationships between malnutrition and the maturation of the pituitary-gonadal axis in developing male rats. As can be noted below in which an age-matched protein-calorie malnourished rat is illustrated next to a well-fed animal, the effects of a low protein diet on body growth are demonstrable. Placing a rat on a low, 8% protein diet beginning at 20 days of age leads to a delay in the onset of puberty, requiring the animal to take nearly twice the time normally needed to reach sexual maturation. Profiles of the gonadotrophic hormones and of the sex steroids in the malnourished animals remain at prepubertal levels throughout their time on the diet. Morphological analyses of the pituitary gland, prostate and testes by light and electron microscopy support the conclusion that these animals are sexually immature and that the activity of their biosynthetic pathways is severely compromised.
a low protein (open circles) diet between 20 and 50 days of age.
Interestingly, after prolonged exposure to a low protein diet, intratesticular levels of testosterone rise which, together with other factors controlling the formation of sperm, stimulates spermatogenesis even though plasma concentrations of LH, FSH and testosterone are well below those of normal animals. On the other hand, once malnourished animals are fed a normal diet, they rapidly become sexually mature. The next question being investigated with my colleagues is the effect of malnutrition on gene expression in the cells of the pituitary gland of male rats.
Allen D, Herbert DC, McMahan CA, Rotrekl V, Sobol RW, Wilson SH, Walter CA. (2008) Mutagenesis Is Elevated in Male Germ Cells Obtained from DNA Polymerase-beta Heterozygous Mice. Biol Reprod. 2008 Jul 23.
Shirasawa N, Sakuma E, Wada I, Naito A, Horiuchi O, Mabuchi Y, Kanai M, Herbert DC, Soji T. (2007) Intercellular communication within the rat anterior pituitary: XIV electron microscopic and immunohistochemical study on the relationship between the agranular cells and GnRH neurons in the dorsal pars tuberalis of the pituitary gland. Anat Rec (Hoboken). 2007 Nov;290(11):1388-98.
Street KA, Xu G, Hall KL, Intano GW, McCarrey JR, Herbert DC, Kilimann MW, Walter CA. (2005) Rat synapsin 1 promoter mediated transgene expression in testicular cell types. DNA Cell Biol. 2005 Feb;24(2):133-40.
Hara, M., D.C. Herbert, T. Taniguchi, A. Hattori, R. Ohtani-Kaneko, M. Iigo, Y. Kato and K. Hirata (1998) Effects of a low-protein diet on prolactin- and growth hormone-producing cells in the rat pituitary gland. Anat. Rec. 251:37-43.
Herbert, D.C., P.C. Supakar and A.K. Roy (1995) Male Reproduction. In: Reproductive Toxicology, 2nd edition. R. J. Witorsch, ed. Raven Press, New York, pp. 3-21.
Herbert DC, Yashiro T, Muraki T, Okano T, Hattori A, Suzuki T. (1993) Quantitative morphological analysis of the pituitary gland in protein-calorie malnourished rats. Anat Rec. 1993 Jan;235(1):121-5.