Another Roundup "surprise"

Click Here to Add Comment

Subject:  Another Roundup "surprise"
Date:     Fri, 31 May 2002 10:17:21 -0400
From:      Stephen Tvedten <steve@getipm.com>
Organization:     Get Set Inc. (www.getipm.com)

To:     Paul Helliker <phelliker@cdpr.ca.gov>
          Director, State of California, Department of Pesticide Regulation 

cc:    Christine Whitman whitman.christine@epa.gov

Seems that scientists have suddenly woken up and realised how dangerous OPs can be? What surprises us is that they didn't spot the problems sooner what with the OP action taking place at the phosphorus atom and phosphorus being vital in all these functions, including fertility.

Perhaps they forgot too that cholesterol is the basis for the hormones and if the OP interferes with its conversion we end up with hormone imbalances?

The following again from the Ban GE list.

http://www.unm.edu/~hoon/RR.html
Roundup Inhibits Steroidogenesis by Disrupting Steroidogenic Acute Regulatory (StAR) Protein Expression

 Lance P. Walsh,1 Chad McCormick,1 Clyde Martin,2 and Douglas M. Stocco1

1Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, USA

2Department of Mathematics, Texas Tech University, Lubbock, Texas, USA Abstract Recent reports demonstrate that many currently used pesticides have the capacity to disrupt reproductive function in animals. Although this reproductive dysfunction is typically characterized by alterations in serum steroid hormone levels, disruptions in spermatogenesis, and loss of fertility, the mechanisms involved in pesticide-induced infertility remain unclear. Because testicular Leydig cells play a crucial role in male reproductive function by producing testosterone, we used the mouse MA-10 Leydig tumor cell line to study the molecular events involved in pesticide-induced alterations in steroid hormone biosynthesis. We previously showed that the organochlorine insecticide lindane and the organophosphate insecticide Dimethoate directly inhibit steroidogenesis in Leydig cells by disrupting expression of the steroidogenic acute regulatory (StAR) protein.

StAR protein mediates the rate-limiting and acutely regulated step in steroidogenesis, the transfer of cholesterol from the outer to the inner mitochondrial membrane where the cytochrome P450 side chain cleavage (P450scc) enzyme initiates the synthesis of all steroid hormones.

In the present study, we screened eight currently used pesticide formulations for their ability to inhibit steroidogenesis, concentrating on their effects on StAR expression in MA-10cells. In addition, we determined the effects of these compounds on the levels and activities of the P450scc enzyme (which converts cholesterol to pregnenolone) and the

3ß-hydroxysteroid dehydrogenase (3ß-HSD) enzyme (which converts pregnenolone to progesterone). Of the pesticides screened, only the pesticide Roundup inhibited dibutyryl [(Bu)2]cAMP stimulated progesterone production in MA-10 cells without causing cellular toxicity. Roundup inhibited steroidogenesis by disrupting StAR protein expression, further demonstrating the susceptibility of StAR to environmental pollutants.

Key words: chemical mixtures, cytochrome P450 side chain cleavage, environmental endocrine disruptor, 3ß-hydroxysteroid dehydrogenase, Leydig cells, Roundup, steroid hormones, steroidogenesis, steroidogenic acute regulatory protein. Environ Health Perspect 108:769-776 (2000). [Online 12 July 2000] http://ehpnet1.niehs.nih.gov/docs/2000/108p769-776walsh/abstract.html

Address correspondence to D.M. Stocco, Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX 79409 USA.

Telephone: (806) 743-2505.

Fax: (806) 743-2990. E-mail: doug.stocco@ttmc.ttuhsc.edu

If you would like to be included in our mailing list for continuing information on pesticides, Email Us..

TOP