Arginase Alteration in the Reproductive System of Alloxan-Diabetic Dogs

Abstract

Abstract. This study was conducted to evaluate possible alteration in the activity of arginase, an important enzyme of cell proliferation and vascular smooth muscle contraction regulator in diabetics, that may be correlated with low fertility in diabetic patients. In this investigation, 6 apparently healthy adult male dogs were selected and divided in two groups, diabetics and non-diabetics. Diabetes mellitus was induced in one group by intravenous (IV) injection of alloxan (100 mg/kg). Dogs with a fasting blood glucose (FBS) of more than 200 mg/dl were considered to be diabetic. Four weeks following induction of diabetes mellitus, the animals in both groups were anesthetized by an IV injection of sodium thiopental. Livers and whole reproductive systems, including the testes, penis, urethra, and prostate, were dissected. The epididymides, corpus cavernosum, corpus spongiosum, penile urethra, and vas deferens were also dissected and removed from the reproductive system. Arginase activity and total protein were measured by the urea and Lowry's methods respectively in above mentioned sections. Plasma testosterone was determined by the radioimmunoassay method. The results showed significantly (P<0.05) increased arginase specific activity (ASA) in the liver, epididymis, prostate, corpus cavernosum and corpus spongiosum of the diabetic dogs. In the reproductive system of the diabetic dog, the maximum and minimum ASA was seen in the corpus cavernosum and testes, respectively (105.12 ± 8.76 vs. 25.0 ± 0.55). No such variation was observed in the ASA of normal dogs (39.0 ± 5.47 vs. 25.0 ± 5.47). There was no significant difference in plasma testosterone level between the groups. In conclusion, diabetes increased the ASA in liver, prostate, epididymis, corpora cavernosa, and corpora spongiosum of the male dogs and may contribute to erectile dysfunction or low fertility in diabetics. Key words: Arginase, Diabetes mellitus, Dog, Reproductive system (J. Reprod. Dev. 53: [317][318][319][320][321] 2007) iabetes mellitus (DM) is a chronic endocrine/ m e t a b o l i c d i s o r d e r w i t h d e v e l o p i n g pathological complications. The major chronic complications associated with diabetes include retinopathy, neuropathy, nephropathy, and atherosclerosis in the coronary and peripheral circulation [1]. Lower pregnancy rates have been associated with basic fertility potential in diabetic men, and variations in semen quality have been reported in these patients [2,3]. Semen analysis may reveal decreased sperm motility and density, abnormal morphology, and generally increased seminal plasma abnormalities. In addition, diabetic men may have decreased serum testosterone levels due to impaired Leydig cell function [4] or a decrease in polyamines, which are required for androgen synthesis [5].Insulin can cross the blood-testis barrier, but its level in seminal plasma has not been shown to correlate significantly with semen parameters [6]. Abnormal sperm morphology in diabetic men is

Germ cell abnormalities in streptozotocin induced diabetic mice do not correlate with blood glucose level

“…Although, the serum testosterone level declined significantly at the end of 36 days in STZ treated group, subsequent estimation on 72 day did not show any difference between control and diabetic groups. The review of earlier studies on the effect of hyperglycemia on plasma testosterone level has demonstrated conflicting results [16][17][18][19] possibly due to differences in study models and diabetes induction methods. With the decline in testosterone level at 36 days interval, we speculated an aberrant spermatogenesis in diabetic animals.…”

Endocrine profile and testicular histomorphometry in adult rat offspring of diabetic mothers

“…Two parallel mechanisms were proposed to cause diabetes-related alterations in Leydig cells: (1) the effect of hypoinsulinemia on serum LH levels and (2) the combined effects of the decreased levels of LH and insulin on Leydig cells [25]. Moreover, diabetes mellitus was reported to alter the activity of arginase (an enzyme important in cell proliferation) in the reproductive system, which may impair Leydig cell proliferation [28].…”

<i>Gongronema Latifolium</i> delays gastric emptying of semi-solid meals in diabetic dogs

“…Diabetes was confirmed at one week after the alloxan injection by the presence of fasting blood glucose level of above 11.10 mmol/L (Jelodar et al, 2007). Polyuria and polydipsia, the clinical signs of diabetes, were also noted.…”

“…Diabetes mellitus was induced in dogs used for the study by intravenous (IV) injection of alloxan monohydrate (Sigma, USA) at a dose of 100 mg/kg (Jelodar et al, 2007;Kim et al, 2006). The dogs were fasted for 24 hours prior to the diabetes induction (Kim et al, 2006).…”