アブストラクト(19巻1号:The Bulletin of Kanagawa Dental College)

The Bulletin of Kanagawa Dental College

English

Title : Regulation of the Steroidgenesis by Submandibular Gland in Rat Testis
Subtitle : ORIGINAL ARTICLES
Authors : Takayuki Nishimura
Authors(kana) :
Organization : Department of Biochemistry, Kanagawa Dental College
Journal : The Bulletin of Kanagawa Dental College
Volume : 19
Number : 1
Page : 11-21
Year/Month : 1991 / 3
Article : Original article
Publisher : Kanagawa Odontological Society
Abstract : [Abstract] To investigate the effect of sialoadenectomy (surgical removal of the submandibular gland) on the male reproductive functions, testicular androgen biosynthesis and estrogen formation were studied in the cell homogenate and microsome of the rat testis, incubating with [4-14C]progesterone, [4-14C]17α-hydroxyprogesterone, [4-14C]Δ4 androstenedione and 3H-Δ4 androstenedione in the presence of NADPH. Groups of rats, sialoadenectomized at 3 weeks of age, were sacrificed at 4 or 8 weeks after the gland ablation and those sialoadenectomized at 7 weeks of age were sacrificed at 4 weeks after the operation. The activities of 17α-hydroxylase in cell-free homogenate and 17β-hydroxysteroid dehydrogenase (17β-HSD) in microsome were significantly enhanced and C17-C20 lyase in cell-free homogenate was slightly enhanced by the ectomy in all the instances. The aromatase activities of 11-week aged rats, however, were reduced to 50% of the control by 8 weeks' ectomy. The enhanced 17α-hydroxylase was shown to be a higher affinity of the enzyme for the substrate progesterone than control, demonstrating the Km values in 7-week aged rats were 1.28μM for control and 0.24μM for those operated at 3 weeks of age, and in 11-week aged rats were 0.9μM for control and 0.5μM for those operated at 7 weeks of age. SMG extract (105,000×g, 1 hr, supernatant) suppressed the 17β-HSD activity enhanced by 4 weeks of sialoadenectomized treatment, when the 11-week aged rat microsomes were incubated with the extract. Neither an increase nor a decrease was shown in the plasma testosterone of ectomized rats as compared to the control rats. The effect of the ectomy on the body weight was apparent as early as one week after the operation, showing a less increase in the weight than the control, and the restoration of the weight was not shown up to 11 weeks. The increase of the testis and ventral prostate in weight was retarded at 5 and 11 weeks of age, respectively. These data suggested that the infant rat SMG contains some substances which act on the testis as a regulatory factor, suppressing the Δ4-3-oxo-pathway metabolism and enhancing the estrogen formation. It is concluded that the infant rat SMG initiates the gonadal functions by controlling the steroidgenesis in the testis.
Practice : Dentistry
Keywords : Submandibular Gland, 17α-Hydroxylase, Testis