Neuropeptides in the rat corpus cavernosum and seminal vesicle: effects of age and two types of diabetes.
OBJECTIVE
To observe the development of neuropathic changes in two types of experimental diabetes using changes in concentrations of NPY, CGRP and amines in the corpora cavernosa and seminal vesicles. Type I diabetes was studied in Wistar rats after 12 and 16 weeks of STZ-induced hyperglycaemia, and Type II diabetes was studied in prediabetic GK rats aged 52 weeks. Both were compared with age-matched normal Wistar rats.


METHODS
NPY and CGRP were estimated using radioimmunoassay, and amines using HPLC.


RESULTS
There were significant changes in [CGRP] in the normal corpus cavernosum and in [NPY] in the normal seminal vesicle with age. STZ-diabetes, induced at 10 weeks of age, resulted in significant elevation of [NPY] and [CGRP] in the corpora cavernosa and seminal vesicles after 12 and 16 weeks of hyperglycaemia, relative to age-matched control rats. The GK rats were intolerant of glucose at 52 weeks of age, but did not have raised fasting blood glucose levels. [NPY], [CGRP] and [noradrenaline] in corpora cavernosa were significantly increased in the prediabetic GK animals relative to age-matched Wistar control rats. The seminal vesicles of GK rats showed a significant increase in [NPY], a non-significant increase in [CGRP], and a fall in [noradrenaline] relative to the age-matched Wistar controls.


CONCLUSIONS
The results indicate increased levels of NPY and noradrenaline in autonomic nerves, and of CGRP in sensory nerves, innervating the corpus cavernosum in Type I and in prediabetic Type II GK rats.
Morrison
J F B
JF
Department of Physiology, Faculty of Medicine and Health Sciences, United Arab Emirates University, PO Box 17666, Al Ain, United Arab Emirates. john.morrison@uaeu.ac.ae
Dhanasekaran
S
S
Howarth
F C
FC
D000375:Aging / Q000378:metabolism*; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D015740:Calcitonin Gene-Related Peptide / Q000032:analysis*; D002395:Catecholamines / Q000032:analysis*; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics / Q000378:metabolism*; D003929:Diabetic Neuropathies / Q000378:metabolism; D007172:Erectile Dysfunction / Q000209:etiology / Q000378:metabolism; D005951:Glucose Tolerance Test; D008297:Male; D009478:Neuropeptide Y / Q000032:analysis*; D010413:Penis / Q000737:chemistry* / Q000294:innervation; D011236:Prediabetic State / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011922:Rats, Mutant Strains; D017208:Rats, Wistar; D012669:Seminal Vesicles / Q000737:chemistry* / Q000294:innervation; D013311:Streptozocin; D017779:Sympathetic Fibers, Postganglionic / Q000737:chemistry*
D001786:Blood Glucose; D002395:Catecholamines; D009478:Neuropeptide Y; D013311:Streptozocin; D015740:Calcitonin Gene-Related Peptide